Evaluation of InP-Based Epitaxial Layers by Photoluminescence Measurement

The correlation between the photoluminescence (PL) intensity of either InGaAsP or InGaAs epitaxial layer and the properties of InP substrates was investigated. The PL intensity of epitaxial wafers depended on carrier concentration, the condition of the back surface of the substrate and the structure of epitaxial layers. In the PL intensity measurement, the absorption of luminescence by the substrate itself sometimes causes the reduction in PL intensity. In the case where a pattern was observed at the back of the substrate, which was contaminated by the outgas from a spring in a fluoroware, the measured PL intensity showed an anomalous distribution. However, the quality of epitaxial layers did not change. It is important to consider the effects of the absorption of the substrate and the roughness of the back of the substrate for evaluating the quality of epitaxial layers by PL measurement. 9 refs.